US 8,751,120 B2 · Assignee: Toyota Jidosha Kabushiki · Inventors: Minase; Yuki et al.
Sheet 1 of 8 from the published document. All sheets in the USPTO PDF
A system includes: a shift mechanism; and a position detecting device detecting an operating position of the shift mechanism on the basis of an output signal of a sensor attached to the shift mechanism. An execution mode of a driving force limiting process that limits driving force is set on the basis of the operating position that is detected by the position detecting device. The driving force limiting process is executed on the basis of the execution mode of the driving force limiting process and a vehicle operation state. When it is determined that there is an abnormality in the position detecting device in a state that the driving force limiting process is not executed, setting the execution mode on the basis of the operating position of the shift mechanism is prohibited, and execution of the driving force limiting process is allowed on the basis of the vehicle operation state.
A prime mover, such as an internal combustion engine and an electric motor, is mounted on a vehicle, such as an automobile, as a driving source. In addition, the vehicle includes a shift mechanism that is shifted through driver's operation into a driving position (for example, a position at which the vehicle travels forward or a position at which the vehicle travels backward) or a non-driving position (for example, a parking position or a neutral position). Then, when the shift mechanism is operated to the driving position, driving force is transmitted from the prime mover to wheels. On the other hand, when the shift mechanism is operated to the non-driving position, transmission of driving force from the prime mover to the wheels is interrupted. There is suggested, in a vehicle in which driving force is transmitted from a prime mover to wheels, an execution mode of driving force limitin
1 of 8 drawing sheets so far from the published document, cropped to the drawing. Every sheet is in the USPTO PDF.
What the patent claimed, word for word. All of it is now free to use.
The disclosure of Japanese Patent Application No. 2011-280384 filed on Dec. 21, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
The invention relates to a driving control system for a vehicle.
A prime mover, such as an internal combustion engine and an electric motor, is mounted on a vehicle, such as an automobile, as a driving source. In addition, the vehicle includes a shift mechanism that is shifted through driver's operation into a driving position (for example, a position at which the vehicle travels forward or a position at which the vehicle travels backward) or a non-driving position (for example, a parking position or a neutral position). Then, when the shift mechanism is operated to the driving position, driving force is transmitted from the prime mover to wheels. On the other hand, when the shift mechanism is operated to the non-driving position, transmission of driving force from the prime mover to the wheels is interrupted.
There is suggested, in a vehicle in which driving force is transmitted from a prime mover to wheels, an execution mode of driving force limiting process for reducing driving force that is output from the prime mover is set on the basis of an operating position of a shift mechanism and then the driving force limiting process is executed on the basis of an operation state of the vehicle.
Japanese Patent Application Publication No. 2010-18174 (JP 2010-18174 A) describes a system that executes driving force limiting process when a shift mechanism is operated from a non-driving position to a driving position in a state where an accelerator operation member is operated. In this system, even when the shift mechanism is operated from the non-driving position to the driving position in a state where the power of the prime mover is increased as a result of operation of the accelerator operation member, driving force that is transmitted from the prime mover to wheels is suppressed to a small driving force. Therefore, a feeling of strangeness experienced by a driver as a result of transmission of driving force is suppressed, and a decrease in drivability is suppressed.
Usually, when the operating position of the shift mechanism is detected, the operating position of the shift mechanism is detected on the basis of an output signal of a shift position sensor attached to the shift mechanism. Therefore, if there is an abnormality in a position detecting device that detects the operating position of the shift mechanism, such as an abnormality in the shift position sensor and an abnormality in a device that processes the output signal of the shift position sensor, it is not possible to properly detect the operating position. In the above-described system, if there is an abnormality in the position detecting device, it is not possible to appropriately reduce driving force through the driving force limiting process, so drivability decreases.
The invention provides a driving control system for a vehicle, which is able to properly reduce driving force through driving force limiting process even when there is an abnormality in a position detecting device that detects an operating position of a shift mechanism.
A first aspect of the invention provides a driving control system for a vehicle. The driving control system includes: a shift mechanism that is operated to selectively shift into one of operating positions, that is, a driving position in which driving force that is output from a prime mover is transmitted to a wheel and a non-driving position in which transmission of the driving force from the prime mover to the wheel is interrupted; a position detecting device that detects the operating position of the shift mechanism on the basis of an output signal of a sensor attached to the shift mechanism; and a controller that sets an execution mode of a driving force limiting process that limits the driving force on the basis of the operating position that is detected by the position detecting device, and that executes the driving force limiting process on the basis of the execution mode and a vehicle operation state that is an operation state of the vehicle. In addition, when the controller determines that there is an abnormality in the position detecting device in a state that the driving force limiting process is not executed, the controller prohibits setting the execution mode based on the operating position, and allows the driving force limiting process to be executed on the basis of the vehicle operation state.
In this way, the driving control system according to the first aspect of the invention is able to properly reduce driving force through the driving force limiting process even when there is an abnormality in the position detecting device that detects the operating position of the shift mechanism.
A second aspect of the invention provides a driving control system for a vehicle. The driving control system includes: a shift mechanism that is operated to selectively shift into one of operating positions, that is, a driving position in which driving force that is output from a prime mover is transmitted to a wheel and a non-driving position in which transmission of the driving force from the prime mover to the wheel is interrupted; a position detecting device that detects the operating position of the shift mechanism on the basis of an output signal of a sensor attached to the shift mechanism; and a controller that sets an execution mode of a driving force limiting process that limits the driving force on the basis of the operating position that is detected by the position detecting device, and that executes the driving force limiting process on the basis of the execution mode and a vehicle operation state that is an operation state of the vehicle. In addition, when the controller determines that there is an abnormality in the position detecting device in a state that the driving force limiting process is being executed, the controller holds the execution mode that has been set immediately before the abnormality occurs.
In this way, the driving control system according to the second aspect of the invention is able to properly reduce driving force through the driving force limiting process even when there is an abnormality in the position detecting device that detects the operating position of the shift mechanism.
A third aspect of the invention provides a driving control system for a vehicle. The driving control system includes: a shift mechanism that is operated to selectively shift into one of operating positions, that is, a driving position in which driving force that is output from a prime mover is transmitted to a wheel and a non-driving position in which transmission of the driving force from the prime mover to the wheel is interrupted; a position detecting device that detects the operating position of the shift mechanism on the basis of an output signal of a sensor attached to the shift mechanism; and a controller that sets an execution mode of a driving force limiting process that limits the driving force on the basis of the operating position that is detected by the position detecting device, and that executes the driving force limiting process on the basis of the execution mode and a vehicle operation state that is an operation state of the vehicle. In addition, when the controller determines that there is an abnormality in the position detecting device in a state that the driving force limiting process is not executed, the controller prohibits execution of the driving force limiting process.
In this way, the driving control system according to the third aspect of the invention is able to properly reduce driving force through the driving force limiting process even when there is an abnormality in the position detecting device that detects the operating position of the shift mechanism.
A fourth aspect of the invention provides a driving control system for a vehicle. The driving control system includes: a shift mechanism that is operated to selectively shift into one of operating positions, that is, a driving position in which driving force that is output from a prime mover is transmitted to a wheel and a non-driving position in which transmission of the driving force from the prime mover to the wheel is interrupted; a position detecting device that detects the operating position of the shift mechanism on the basis of an output signal of a sensor attached to the shift mechanism; and a controller that sets an execution mode of a driving force limiting process that limits the driving force on the basis of the operating position that is detected by the position detecting device, and that executes the driving force limiting process on the basis of the execution mode and a vehicle operation state that is an operation state of the vehicle. In addition, when there is an abnormality in the position detecting device, the controller uses an operating position of the shift mechanism that is estimated on the basis of a driving state of the vehicle, as a setting parameter for setting the execution mode of the driving force limiting process, instead of the operating position that is detected by the position detecting device.
In this way, the driving control system according to the fourth aspect of the invention is able to properly reduce driving force through the driving force limiting process even when there is an abnormality in the position detecting device that detects the operating position of the shift mechanism.
Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
FIG. 1 is a schematic view that shows the schematic configuration of a driving control system for a vehicle according to a first embodiment of the invention;
FIGS. 2A and 2B are a flowchart that shows the execution procedure of a drive limiting routine according to the first embodiment;
FIG. 3 is a graph that shows the correlation between an amount of reduction of driving force and a vehicle acceleration through driving force limiting process;
FIG. 4 is a graph that shows the correlation between a vehicle acceleration, a vehicle speed and a determination value in the driving force limiting process;
FIG. 5 is a flowchart that shows the execution procedure of a drive limiting routine according to a second embodiment of the invention;
FIG. 6 is a flowchart that shows the execution procedure of the drive limiting routine; and
FIGS. 7A and 7B are a flowchart that shows the execution procedure of a drive limiting routine according to a third embodiment of the invention.
Hereinafter, a driving control system for a vehicle according to a first embodiment of the invention will be described. As shown in FIG. 1, an internal combustion engine 2 and an automatic transmission 3 are mounted on a vehicle 1. The internal combustion engine 2 is a drive source. The automatic transmission 3 automatically executes gear shift operation. Then, driving force output from the internal combustion engine 2 is transmitted to wheels 4 via the automatic transmission 3, and the like. By so doing, the wheels 4 rotate, and the vehicle 1 travels. The automatic transmission 3 includes a plurality of gears. The automatic transmission 3 is able to change a combination of those plurality of gears such that any one of a plurality of predetermined gear positions is selected and established. In addition, the automatic transmission 3 is able to transmit driving force, which is output from the internal combustion engine 2, to the wheels 4 or interrupt transmission of driving force that is output from the internal combustion engine 2.
A shift mechanism 5 is installed in the vehicle 1. The shift mechanism 5 is used to change an operation mode of the automatic transmission 3. A select lever 6 of the shift mechanism 5 is coupled to the automatic transmission 3 (specifically, a shift fork thereof). Then, the select lever 6 is operated to shift into any one of a plurality of operating positions by a driver. The plurality of operating positions include a parking position, a reverse travel (reverse) position, a neutral position and a forward travel (drive) position. Hereinafter, the operation mode of the automatic transmission 3 for each operating position of the select lever 6 will be described.
When the select lever 6 is operated to the parking position, rotation of the wheels 4 is prohibited through meshing of the gears in the automatic transmission 3, and transmission of driving force, which is output from the internal combustion engine 2, to the wheels 4 is interrupted. When the select lever 6 is operated to the neutral position, the above-described prohibition of rotation of the wheels 4 through meshing of the gears in the automatic transmission 3 is released, and transmission of driving force, which is outputted from the internal combustion engine 2, to the wheels 4 is interrupted. When the select lever 6 is operated to the drive position, driving force that is outputted from the internal combustion engine 2 is transmitted to the wheels 4 in a forward rotation direction. At this time, the vehicle 1 is allowed to travel forward. When the select lever 6 is operated to the reverse position, driving force that is outputted from the internal combustion engine 2 is transmitted to the wheels 4 in a reverse rotation direction. At this time, the vehicle 1 is allowed to travel backward.
An electronic control unit 7 (controller) is mounted on the vehicle 1. The electronic control unit 7 executes various controls associated with the internal combustion engine 2, the automatic transmission 3, and the like. In addition, various sensors are attached to the vehicle 1. Those sensors, for example, include a vehicle speed sensor 8 and an accelerator position sensor 10. The vehicle speed sensor 8 is used to detect a travel speed (vehicle speed SPD) of the vehicle 1. The accelerator position sensor 10 is used to detect an operation amount (accelerator operation amount ACC) of an accelerator operation member 9 (accelerator pedal, accelerator lever, or the like). Other than that, a shift position sensor 11, and the like, are also provided. The shift position sensor 11 is attached to the shift mechanism 5, and is used to detect an operating position (shift position SP) of the shift mechanism 5 (specifically, the select lever 6 thereof). Output signals of various sensors are input to the electronic control unit 7. A drive circuit for driving the internal combustion engine 2, a drive circuit for driving the automatic transmission 3, and the like, are connected to the electronic control unit 7.
The electronic control unit 7 adjusts driving force, which is output from the internal combustion engine 2, on the basis of the accelerator operation amount ACC, or the like. In addition, the electronic control unit 7 shifts the gear position in the automatic transmission 3 on the basis of the accelerator operation amount ACC, the vehicle speed SPD and the shift position SP.
At the time of a start of the vehicle 1, the driver usually shifts the operating position of the select lever 6 from the non-driving position (the parking position or the neutral position) to the driving position (the drive position or the reverse position) and then operates the accelerator operation member 9 in an off state to an on state. However, when the driver is hurrying, an operation from an off state of the accelerator operation member 9 to an on state thereof (hereinafter, referred to as "on operation" where appropriate) may be performed earlier than an operation to shift from the non-driving position of the select lever 6 to the driving position thereof. In this case, even when the driver has an intention of performing the above-described usual operation, an operation different from the normal operation, that is, a shift from the non-driving position of the select lever 6 to the driving position thereof is actually performed in a state where the accelerator operation member 9 undergoes on operation.
When the driver unintentionally performs such an operation different from the usual operation, the behavior of the vehicle 1, which is expected by the driver, may differ from an actual behavior. More specifically, the driver intends to start the vehicle 1 when the driver operates the accelerator operation member 9 to an on state. In contrast to this, actually, when the select lever 6 is shifted from the non-driving position to the driving position after the accelerator operation member 9 undergoes on operation, the driving force of the internal combustion engine 2 is transmitted to the wheels 4, and the vehicle 1 starts moving. Such a lag of the behavior of the vehicle 1 makes the driver experience a feeling of strangeness, so it becomes one of factors that decrease the drivability of the vehicle 1.
In addition, while the vehicle 1 is travelling forward, the position of the driver seated on a seat is usually natural. In contrast to this, while the vehicle 1 is travelling backward, the driver mostly takes an unreasonable position, such as a position that the body is twisted to watch the backward of the vehicle while the driver is seated on the seat. Therefore, while the vehicle 1 is travelling backward, it is difficult to minutely operate the accelerator operation member 9 as compared with while the vehicle 1 is travelling forward, and it is also difficult to minutely adjust driving force that is output from the internal combustion engine 2 and that is transmitted to the wheels 4. Thus, while the vehicle 1 is travelling backward, the behavior of the vehicle 1, which is expected by the driver, tends to differ from an actual behavior. Therefore, while the vehicle 1 is travelling backward, it easily leads to a decrease in drivability.
In the present embodiment, when the select lever 6 is operated to shift from the non-driving position (the parking position or the neutral position) to the reverse position in a state where the accelerator operation member 9 undergoes an operation, a driving force limiting process is executed. In the driving force limiting process, driving force that is output from the internal combustion engine 2 is suppressed as compared with when usual operation is performed. In the present embodiment, when the select lever 6 is operated to shift from the non-driving position to the drive position in a state where the accelerator operation member 9 undergoes an operation, the driving force limiting process is not executed.
The system according to the present embodiment executes the above-described driving force limiting process when an operation from an off state of the accelerator operation member 9 to an on state thereof is performed before the operating position of the select lever 6 is shifted from the non-driving position to the reverse position, that is, for example, when the driver intends to hastily start the vehicle 1. By so doing, even when the select lever 6 is shifted from the non-driving position to the reverse position in a state where the driver operates the accelerator operation member 9 to an on state, the above-described driving force limiting process is executed, so driving force that is output from the internal combustion engine 2 is suppressed. Therefore, a feeling of strangeness experienced by the driver as a result of a start of travel of the vehicle 1 through transmission of driving force to the wheels 4 is suppressed, so a decrease in the drivability of the vehicle 1 is suppressed.
In addition, while the vehicle 1 is travelling forward, that is, when it is possible to minutely operate the accelerator operation member 9, driving force is not limited through the driving force limiting process, so the driving force of the vehicle 1 is adjusted through actual driver's operation of the accelerator operation member 9. Then, while the vehicle 1 is travelling backward, that is, when it is difficult to minutely operate the accelerator operation member 9, driving force is limited through the driving force limiting process, so the vehicle 1 is operated in a small driving force state and a change in the behavior of the vehicle 1 is gentle. Thus, a decrease in drivability is suppressed. In the above-described embodiment, driving force that is output from the internal combustion engine 2 is properly limited on the basis of the travel direction of the vehicle 1.
In the present embodiment, the driving force limiting process is stopped when one of the following conditions 1 and 2 is satisfied while the driving force limiting process is being executed. The condition 1 is that the operating position of the shift mechanism 5 is set at a position other than the reverse position. The condition 2 is that a driving force that should be output from the internal combustion engine 2 on the basis of the accelerator operation amount ACC is smaller than a control driving force that is a driving force suppressed through the driving force limiting process, for example, when driver's on operation of the accelerator operation member 9 is released and the accelerator operation amount ACC becomes "0".
Here, in the present embodiment, the shift position SP is detected through arithmetic processing that is executed by the electronic control unit 7 on the basis of an output signal of the shift position sensor 11. Therefore, when there is an abnormality in a position detecting device for detecting the shift position SP, such as the shift position sensor 11, the electronic control unit 7 and a line that connects those shift position sensor 11 and electronic control unit 7, it is not possible to properly detect the shift position SP. In this case, it is not possible to appropriately suppress driving force through the driving force limiting process, so drivability decreases.
In the present embodiment, when there occurs an abnormality in the position detecting device for detecting the shift position SP, the shift position SP is not used as a setting parameter for setting the execution mode (specifically, determining whether to execute) the driving force limiting process. Then, at this time, determination as to whether the vehicle 1 is travelling forward (hereinafter, may be referred to as "forward travel determination") is made on the basis of the driving state of the vehicle 1 (in the present embodiment, the gear position of the automatic transmission 3, which is recognized by the electronic control unit 7), and a result of the determination is used as the above-described setting parameter. In the present embodiment, the electronic control unit 7 functions as a speed ratio detecting device that detects a speed ratio of the automatic transmission 3. In addition, in the present embodiment, the execution mode of the driving force limiting process, which is set on the basis of the operating position of the shift mechanism 5, is whether to execute the driving force limiting process.
In the system according to the present embodiment, at the time when the vehicle 1 travels forward, as the travel speed of the vehicle 1 increases, the gear position of the automatic transmission 3 is changed to a high-speed-side gear position having a smaller speed ratio. On the other hand, at the time when the vehicle 1 travels backward, it is not assumed that the travel speed increases as in the case where the vehicle 1 travels forward. Therefore, irrespective of the travel speed of the vehicle 1, a lowest-speed-side gear position having a large speed ratio is set as the gear position of the automatic transmission 3. By so doing, in the vehicle 1, when a gear position other than the lowest-speed-side gear position is set as the gear position of the automatic transmission 3, it is possible to accurately determine that the vehicle 1 is travelling forward. In the present embodiment, on the basis of the above concept, forward travel determination is made on the basis of the gear position of the automatic transmission 3, which is detected by the electronic control unit 7.
According to the present embodiment, even when there is an abnormality in the position detecting device for detecting the shift position SP, it is possible to accurately determine that the vehicle 1 is travelling forward through the above-described forward travel determination. Therefore, it is possible to reduce erroneous determination that the shift mechanism 5 is operated to the reverse position although the shift mechanism 5 is actually operated to the drive position or erroneous determination that the shift mechanism 5 is operated to the drive position although the shift mechanism 5 is actually operated to the reverse position. Thus, it is possible to reduce the following state 1 or 2 due to such erroneous determination. State 1: Due to erroneous determination that the shift mechanism 5 is operated to the reverse position although the shift mechanism 5 is actually operated to the drive position in a state that the driving force limiting process is not executed, the driving force limiting process is started, and driving force that is output from the internal combustion engine 2 is unnecessarily reduced. State 2: Due to erroneous determination that the shift mechanism 5 is operated to the drive position although the shift mechanism 5 is actually operated to the reverse position in a state that the driving force limiting process is being executed, the driving force limiting process is stopped.
According to the present embodiment, when there occurs an abnormality in the position detecting device, it is possible to use the result of forward travel determination based on the gear position of the automatic transmission 3 as the setting parameter for setting the execution mode of the driving force limiting process without using the operating position (shift position SP) detected by the position detecting device. Therefore, even when there is an abnormality in the position detecting device, it is possible to suppress a start of the driving force limiting process at an undesirable timing or a stop of the driving force limiting process at an undesirable timing, so it is possible to properly reduce driving force through the driving force limiting process.
Hereinafter, the execution procedure and operation of a drive limiting routine that includes the above-described driving force limiting process will be described in detail with reference to the flowchart shown in FIGS. 2A and 2B. Note that a series of processes shown in the flowchart are periodically executed by the electronic control unit 7 as, for example, an interrupt at predetermined time intervals.
As shown in FIGS. 2A and 2B, the routine initially determines whether there is an abnormality in the position detecting device (S101). Here, an abnormality of the position detecting device is determined by determining any one of an abnormality of the shift position sensor 11, an abnormality of the electronic control unit 7 and an abnormality (break or short-circuit) of a line that connects the shift position sensor 11 and electronic control unit 7.
When it is not determined that there is an abnormality in the position detecting device (NO in S101), the shift position SP is acquired (S102). In this case, in the following processes, the operating position of the shift mechanism 5, which is determined from the shift position SP, is used as the setting parameter for setting the execution mode of the driving force limiting process.
On the other hand, when it is determined that there is an abnormality in the position detecting device (YES in S101), the gear position of the automatic transmission 3 is acquired, and forward travel determination is made on the basis of the gear position (S103). Then, on the basis of the result of the forward travel determination, the operating position of the shift mechanism 5 at the time of the forward travel determination is identified and stored. Specifically, when it is determined that the vehicle 1 is travelling forward through the forward travel determination, the drive position is stored as the operating position of the shift mechanism 5 at the time when it is determined that the vehicle 1 is travelling forward. In addition, when it is not determined that the vehicle 1 is travelling forward through the forward travel determination, the operating position stored at the time when the process has been executed last time is stored as the operating position of the shift mechanism 5 at the time of the forward travel determination. Then, the thus stored operating position of the shift mechanism 5 is used as the above-described setting parameter in the following processes.
After that, it is determined whether an execution flag is set to an off state (S104). The execution flag is set to an on state when the driving force limiting process (S108) is started. On the other hand, the execution flag is set to an off state when the driving force limiting process is stopped. In the process of S104, on the basis of the state of the execution flag, it is determined whether the driving force limiting process is stopped.
When the execution flag is set to an off state (YES in S104), it is determined that the driving force limiting process is not executed, and then it is determined whether to start the driving force limiting process (S105 and S106). Here, when the following conditions 3 and 4 both are satisfied, it is determined to start the driving force limiting process. Condition 3: The accelerator operation member 9 is operated to an on state. Specifically, the accelerator operation amount ACC is larger than a predetermined value. Condition 4: The operating position of the shift mechanism 5 at the time when the routine is executed last time is the non-driving position, and the operating position of the shift mechanism 5 at the time when the routine is executed this time is the reverse position.
When at least one of these conditions 3 and 4 is not satisfied (NO in S105 or NO in S106), it is determined not to start the driving force limiting process. Then, the routine once ends without executing the following processes.
On the other hand, after that, when the routine is repeatedly executed and both the conditions 3 and 4 are satisfied (YES in S105 and YES in S106), the execution flag is set to an on state (S107), and the driving force limiting process is started (S108). The execution procedure of the driving force limiting process will be described later. After that, unless the execution flag is set to an off state (NO in S104), the driving force limiting process is continued.
While the driving force limiting process is being executed (NO in S104 or YES in S106), processes associated with an end of the driving force limiting process (processes of S109 to S112) are executed. Specifically, initially, it is determined whether one of the condition 1 and the condition 2 is satisfied. When both the condition 1 and the condition 2 are not satisfied (NO in S109 and NO in S110), the driving force limiting process is not stopped but continued (the processes of S111 and S112 are skipped). After that, when the processes of the routine are repeatedly executed and the condition 1 is satisfied (YES in S109) or when the condition 2 is satisfied (YES in S110), the driving force limiting process is stopped (S111), and the execution flag is set to an off state (S112), after which the routine once ends. By so doing, thereafter, limiting driving force that is output from the internal combustion engine 2 is stopped, and the driving force is adjusted so as to coincide with a required driving force that is a driving force that should be output from the internal combustion engine 2 on the basis of the accelerator operation amount ACC.
In this way, in the drive limiting routine according to the present embodiment, in the process of determining whether to execute the driving force limiting process (S106, S109), the operating position that is acquired from the shift position SP is used when there is no abnormality in the position detecting device, and the operating position that is acquired from the gear position of the automatic transmission 3 is used when there is an abnormality in the position detecting device. Therefore, even when there is an abnormality in the position detecting device, it is possible to properly reduce driving force through the driving force limiting process.
Hereinafter, a mode of limiting the driving force in the driving force limiting process (the process of step S108 in FIG. 2B) will be described in detail with reference to FIG. 3 and FIG. 4. In the driving force limiting process, driving force that is output from the internal combustion engine 2 is suppressed by reducing the driving force by an amount of reduction. Thus, as the amount of reduction is increased, the degree of suppressing the driving force through the driving force limiting process increases. The degree of suppressing driving force is changed on the basis of an acceleration (vehicle acceleration D) in a travel direction of the vehicle 1. The vehicle acceleration D is obtained on the basis of a detected signal of the vehicle speed sensor 8. For example, as the vehicle acceleration D increases, the degree of suppressing driving force that is output from the internal combustion engine 2 is increased by increasing the amount of reduction. More specifically, for example, as shown in FIG. 3, when the vehicle acceleration D is lower than a determination value HA, the degree of suppressing the driving force is set to "0" by setting the amount of reduction to "0". On the other hand, when the vehicle acceleration D is higher than or equal to the determination value HA, as the vehicle acceleration D increases with respect to the determination value HA, the degree of suppressing driving force that is output from the internal combustion engine 2 is increased to above "0" by setting the amount of reduction to above "0".
By executing the driving force limiting process as described above, driving force is suppressed such that the driver does not experience a feeling of strangeness while unnecessary suppression of driving force that is output from the internal combustion engine 2 is avoided. In addition, in a situation that the vehicle 1 is escaped of a muddy road, the driver may repeatedly operate the select lever 6 to shift between the non-driving position and the driving position. At this time, the select lever 6 may be shifted from the non-driving position to the reverse position in a state where the accelerator operation member 9 is operated to an on state. When the vehicle 1 is driven out of a slushy road in this way, even when the select lever 6 is shifted from the non-driving position to the reverse position in a state where the accelerator operation member 9 is operated to an on state, the vehicle acceleration D is hard to increase, so the degree of suppressing the driving force through the driving force limiting process reduces. Thus, it is possible to prevent a state that suppressing the driving force through the driving force limiting process inhibits the vehicle 1 from being driven out of a slushy road. Thus, the drivability of the vehicle 1 improves, for example, when the vehicle 1 is driven out of a slushy road.
The determination value HA that is used in the driving force limiting process is variably set on the basis of the vehicle speed SPD so as to be an optimal value determined in advance through an experiment, or the like. The determination value HA, for example, changes with the vehicle speed SPD as indicated by the solid line in FIG. 4. As is apparent from FIG. 4, when vehicle speed SPD is lower than a predetermined speed KB, the determination value HA is constant at an optimal value determined in advance through an experiment, or the like. In addition, when the vehicle speed SPD is higher than or equal to the predetermined speed KB and is lower than a reference speed KA, the determination value HA is gradually reduced with an increase in the vehicle speed SPD. Furthermore, when the vehicle speed SPD is higher than or equal to the reference speed KA, the determination value HA is set to "0". Thus, at the time of executing the driving force limiting process, when the vehicle speed SPD is higher than or equal to the reference speed KA, the degree of suppressing driving force that is output from the internal combustion engine 2 is increased to above "0" on the basis of the vehicle acceleration D irrespective of a magnitude relationship between the vehicle acceleration D and the determination value HA. That is, in order to increase the degree of suppressing driving force that is output from the internal combustion engine 2 to above "0" as described above, the amount of reduction is set to a value that is larger than "0" on the basis of the vehicle acceleration D. In this case, at the time of executing the driving force limiting process, when the vehicle speed SPD is higher than the reference speed KA, that is, when the driver tends to experience a feeling of strangeness, it is possible to suppress the feeling of strangeness by adequately suppressing the driving force.
As described above, according to the present embodiment, advantageous effects described below are obtained.
1) When there is an abnormality in the position detecting device, the determination result as to the forward travel determination made on the basis of the gear position of the automatic transmission 3, which is acquired by the electronic control unit 7 at this time instead of using the shift position SP, as the setting parameter for setting the execution mode of the driving force limiting process. Therefore, even when there occurs an abnormality in the position detecting device, when the reliability of the operating position, which is detected by the position detecting device, is low, it is possible to prohibit setting the execution mode on the basis of the operating position, so it is possible to suppress a start of the driving force limiting process at an undesirable timing or a stop of the driving force limiting process at an undesirable timing, and it is possible to properly reduce driving force through the driving force limiting process. In a vehicle on which an automatic transmission that automatically carries out gear shift operation is mounted, as the travel speed increases, the speed ratio of the automatic transmission decreases. In addition, the travel speed does not become so high when the vehicle travels backward as to when the vehicle travels forward, so the speed ratio of the automatic transmission at the time when the vehicle travels backward is set so as not to be lower than the speed ratio at the time when the vehicle travels forward. Therefore, in the vehicle on which the automatic transmission is mounted, it may be accurately determined that the vehicle is travelling forward on the basis of the fact that the speed ratio of the automatic transmission is decreased.
In this way, according to the present embodiment, even when there is an abnormality in the position detecting device that detects the operating position of the shift mechanism, it is possible to accurately determine that the vehicle is travelling forward on the basis of the speed ratio of the automatic transmission, so it is possible to accurately set the execution mode of the driving force limiting process on the basis of at least the fact that the shift mechanism is operated to a forward travel position or the fact that the shift mechanical has been operated to the forward travel position.
The description continues in the full USPTO document.
About 6,644 words. The USPTO PDF has it with every drawing.
Fees are due 3.5, 7.5 and 11.5 years after grant. This patent expired on June 10, 2026, so the fee marked "not paid" was the one that went unpaid.
DRIVING CONTROL SYSTEM FOR VEHICLE
Filed Dec 2012 · published Jun 2013Driving control system for vehicle
Filed Dec 2012 · granted Jun 2014Earlier publications, parents and continuations. None of them can still be enforced, or this patent would not be listed.
Prior art cited by the examiner or applicant. Useful when you check your own idea for novelty.
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